Human Nutrition

Question 1

Enzyme that breaks down starch, starch ->? And where it is made

Answer 1

Amylase, starch goes to maltose(broken down to glucose by maltase), made in salivary glands, pancreases and small intestine

Question 2

Enzyme that breaks down proteins, proteins ->? And where it is made

Answer 2

Protease, proteins -> amino acids, made in the stomach (where it is called pepsin), pancreas, small intestine

Question 3

Enzymes that break down lipids, lipids ->? And where it is made

Answer 3

Lipases, lipids -> glycerol 3 fatty acids, made in pancreas small intestine

Question 4

What is bile, and where is it made.

Answer 4

A liquid made in the liver and stored in the gall bladder than helps with lipid digestion, through emulsifi cation

Question 5

What are the two models of enzyme action?

Answer 5

Lock and key model
Induced fit model (enzymes active site is complementary to the substrate)

Question 6

How to prepare a food sample

Answer 6

-break up food with pestle and mortar
-transfer to beaker and add some distilled water
-stir with a glass rod to dissolve some food
-filter the solution to get rid of the solid bits of food

Question 7

Test for glucose

Answer 7

-prepare food ample and transfer 5cm^3 to a test tube
-prepare a water bath at 75*C
-add some Benedict’s locution to the test tube (about 10 drops) using a pipettes
-place in the water bath using test tube holder, leave for 5 mins
-blue -> green/ yellow (low concentrations) or brick red (high concentration)

Question 8

Test for protein

Answer 8

-Prepare a good sample and transfer 2cm^3 to a test tube
-add 2cm^3 of biuret solution to the sample and mix by gently shaking it
-blue -> pink or purple

Question 9

Test for starch

Answer 9

-prepare a food sample and transfer 5cm^3 to a test tube
-add a few drops of iodine solution and gently shake
-browny orange -> blue black

Question 10

Test for lipids

Answer 10

-Prepare a food sample (do not need to filter it)
-transfer about 5cm^3 to a test tube
-use a pipettes to add 3 drops of sudan III to the test tube and gently shake
-if lipids are present a bright red layer will form on top of the test tube

Question 11

Alimentary canal

Answer 11

Mouth -> oesophagus -> stomach -> small intestine -> large intestine -> rectum

Question 12

Mouth

Answer 12

1)Salivary glands in the mouth produce amylase enzyme in the saliva
2)Teeth break down food

Question 13

Oesophagus

Answer 13

-The muscular tube that connects the mouth and stomach
-Uses peristalsis, waves of circular muscle contractions

Question 14

Stomach

Answer 14

It pummels the food with its muscular walls
-produces the protease pepsin
-produces hydrochloride acid to kill bacteria and to give the optimum pH for pepsin to work

Question 15

Liver

Answer 15

Where bile is produced

Question 16

Gall bladder

Answer 16

Where bile is stored

Question 17

Pancreas

Answer 17

Produces protease, amylase and lipase enzymes, releases these into the small intestine

Question 18

Small intestine

Answer 18

Produces protease amylase and lipase enzymes to complete digestion
-where nutrients are absorbed out of the alimentary canal into the blood stream
-the first part of the small intestine is the duodenum and the last part is the ileum

Question 19

Large intestine

Answer 19

-Also called the colon
-where excess water is absorbed

Question 20

Rectum

Answer 20

The last part of the large intestine
-where the faeces is stored

Question 21

Bile function

Answer 21

Neutralises the stomach acid and emulsifies fats as enzymes in the small intestines work best in neutral pH